The present invention relates generally to the field of vehicle safety systems of the type utilizing an inflatable confinement. More particularly, this invention relates to an improved inflating systems for inflating the confinements of such safety devices.
A great deal of attempt is being given to the problem of increasing the safety of passenger vehicles. As well as trying to increase the safety of the vehicle itself, considerable effort is being given to the development of passive restraint systems which will protect the occupants of a vehicle from injury due to impact without the necessity of the occupant taking any positive action.
One type of passive restraint system which has been developed utilizes an inflatable confinement means such as a bag which is automatically inflated in response to a predetermined condition such as impact or upsetting of the vehicle to prevent the occupant from contacting the interior of the vehicle.
Some vehicle safety systems of the type employing inflatable confinements utilize an inflatable confinement means, a stored fluid under pressure in a chamber, and a propellant charge for the generation of hot gas. When a collision of the vehicle is sensed, the propellant charge is ignited and the hot gas resulting therefrom caused to mix with the stored fluid, and the mixture released to inflate the confinement. When the propellant gas is caused to discharge into the fluid storage chamber, some propellants have been found to be so fast burning that even though the fluid chamber outlet is opened at substantially the same time as the propellant gas begins to flow into the fluid storage chamber, a substantial increase in pressure over that of the fluid storage pressure is experienced in the chamber. This could result in the rupturing of the storage chamber with a subsequent failure of the safety system as well as possible injury to the occupants over and above that caused by the accident itself. Attempts to increase the strength of the chamber to withstand the sudden surge of pressure results in increased cost and additional manufacturing complexity.